The present invention relates generally to apparatus for applying or wrapping stretch film to or around palletized loads, products, or articles, and more particularly to a new and improved motor-powered stretch film load-wrapping apparatus for applying stretch film to palletized loads, articles or products, wherein a single motor drive system is incorporated within the apparatus so as to be able to be used for achieving or controlling both the rotational movement of the rotatable boom member, upon which the stretch film roll carriage assembly is mounted, relative to the static boom member, as well as the vertical movements of the stretch film roll carriage assembly relative to the rotatable boom member, so as to achieve various positional dispositions of the stretch film roll carriage assembly, relative to the rotatable boom member, attendant different operational modes of the stretch film roll carriage assembly in accordance with various segments or stages of a stretch film wrapping operation cycle.
In the aforenoted patent application, it was noted that approximately fifty percent (50%) of all stretch film that is manufactured is applied to or wrapped around, for example, palletized loads or products by manual means. It was further noted that such stretch film has been conventionally applied to or wrapped around the palletized loads or products in accordance with either one of two well-known methods or techniques as implemented by the mechanisms or devices disclosed within U.S. Pat. 5,398,884 and 5,458,841 which issued respectively to Stanford on Mar. 21, 1995 and Shirrell on Oct. 17, 1995. It was noted still further that such conventional stretch film application or wrapping techniques, utilizing the disclosed mechanisms or implements, also encountered operational difficulties or drawbacks due, for example, to the fact that the film roll and dispensing mechanisms are quite heavy and cumbersome and yet they must be supported by the operator personnel. In addition, in order to fully or entirely wrap a particular load or product, the operator must either maintain the film roll and the dispensing mechanism at an elevated position so as to be able to wrap or encase upper region portions of the load or product, or alternatively, the operator must bend down while holding the film roll and its dispensing mechanism in order to wrap the film around the lower extremity portions of the palletized loads or products. Such procedures can obviously lead to discomfort, fatigue, and stress-related injuries. Accordingly, the system disclosed within the aforenoted patent application, wherein, for example, the film carriage assembly is movably supported upon a vertical mast by means of a counterweight or counterbalancing system, was developed in order to rectify the operational deficiencies of the aforenoted PRIOR ART manual film wrapping and dispensing systems disclosed within the aforenoted patents.
Obviously, a further alternative to the aforenoted PRIOR ART manually operated stretch film wrapping, dispensing, or application systems is to utilize powered or even fully automated stretch film wrapping, dispensing, or application systems. However, conventional powered or fully automated stretch film wrapping, dispensing, or application systems are known to be relatively complex, costly to manufacture, and require a relatively high degree of maintenance, and there are several reasons for these characteristics or factors. Firstly, in accordance with such conventionally known systems, separate motor drives must be provided for operating and controlling the movements of the rotatable boom member as well as the upward and downward elevational movements of the stretch film roll carriage assembly. Still further, in conjunction with such dual-motor drive systems, it is known that it is further required to incorporate within the control system suitable slip-ring or commutator structure so as to appropriately control the movements of the rotatable boom member and the vertically movable stretch film roll carriage assembly during different portions of the film wrapping operation cycle.
A need therefore exists in the art for a new and improved motor-powered stretch film load-wrapping apparatus for applying stretch film to palletized loads, products, or articles, wherein a single motor drive system is incorporated within the apparatus so as to be able to be used for achieving or controlling both the rotational movement of the rotatable boom member, upon which the stretch film roll carriage assembly is mounted, relative to the static boom member, as well as the vertical movements of the stretch film roll carriage assembly relative to the rotatable boom member, so as to achieve various positional dispositions of the stretch film roll carriage assembly, relative to the rotatable boom member, attendant different operational modes of the stretch film roll carriage assembly in accordance with various segments or stages of a stretch film wrapping operation cycle.
Accordingly, it is an object of the present invention to provide a new and improved motor-powered stretch film dispensing and application or wrapping apparatus for use in connection with the dispensing and wrapping or application of stretch film upon palletized loads, articles, packages, or products.
Another object of the present invention is to provide a new and improved motor-powered stretch film dispensing and application or wrapping apparatus, for use in connection with the dispensing and wrapping or application of stretch film upon palletized loads, articles, packages, or products, which effectively overcomes the various operational disadvantages or drawbacks characteristic of conventional stretch film dispensing and application or wrapping apparat
An additional object of the present invention is to provide a new and improved motor-powered stretch film dispensing and application or wrapping apparatus, for use in connection with the dispensing and wrapping or application of stretch film upon palletized loads, articles, packages, or products, which effectively overcomes the various operational disadvantages or drawbacks characteristic of conventional stretch film dispensing and application or wrapping apparatus as a result of the incorporation therein of a motor-powered system for rotationally driving the rotatable boom member as well as for vertically elevating the stretch film roll carriage assembly.
A further object of the present invention is to provide a new and improved motor-powered stretch film dispensing and application or wrapping apparatus, for use in connection with the dispensing and wrapping or application of stretch film upon palletized loads, articles, packages, or products, which effectively overcomes the various operational disadvantages or drawbacks characteristic of conventional stretch film dispensing and application or wrapping apparatus as a result of the incorporation therein of a single motor drive system for both rotationally driving the rotatable boom member as well as for vertically elevating the stretch film roll carriage assembly.
The foregoing and other objectives are achieved in accordance with the teachings and principles of the present invention through the provision of new and improved motor-powered stretch film dispensing and application or wrapping apparatus which comprises a fixed upright or vertical mast member upon the upper end of which is fixedly mounted or supported a static boom member. A drive motor is fixedly mounted upon the static boom member, and a vertically disposed drive shaft is operatively engaged with a motor output shaft. The drive shaft passes downwardly through the static boom member and the lower end portion of the drive shaft is fixedly mounted within a rotatable boom member so as to cause rotation of the rotatable boom member when the drive motor is operated. A stretch film roll carriage assembly is movably upon a downright or vertically disposed wrapping mast upon the upper end of which the rotatable boom member is supported, and a cable drum is movably mounted upon the vertically disposed drive shaft. One end of a cable is fixedly secured to the cable drum while a second opposite end of the cable is fixedly secured to the stretch film roll carriage assembly. A cable drum lift spring mounted within the rotatable boom member acts upon an undersurface portion of the cable drum so as to bias the cable drum towards a first uppermost position with respect to the drive shaft such that the cable drum will be engaged with the static boom member and thereby be prevented from rotating. Accordingly, when the rotatable boom member is rotated, the cable is wound upon the cable drum thereby causing the stretch film roll carriage assembly to be raised.
First and second solenoid mechanisms are also fixedly mounted upon opposite lateral sides of the static boom member such that actuation rod members thereof can engage upper surface portions of the cable drum when the solenoid mechanisms are individually actuated. The actuation rod members of the solenoid mechanisms have different stroke lengths, and accordingly, when a first one of the solenoid mechanisms is actuated, the cable drum is moved downwardly a first predetermined amount with respect to the static boom member so as to be operatively disengaged from its locked position with respect to the static boom member and be interposed between the static and rotatable boom members. In this manner, the cable drum is permitted in effect to free-wheel or rotate freely with respect to the static and rotatable boom members whereby the stretch film roll carriage assembly is able to be moved downwardly along the downright or wrapping mast under the influence of gravity. Alternatively, when the second one of the solenoid mechanisms is actuated, the cable drum is moved downwardly a second predetermined amount with respect to the static boom member so as to be operatively disengaged from its locked position with respect to the static boom member and be lockingly engaged with the rotatable boom member. In this manner, the cable drum rotates along with the rotatable boom member such that the stretch film roll carriage assembly is maintained at a predetermined elevational position with respect to the palletized load, article, package, or product being wrapped whereby a predetermined portion of the stretch film being wrapped upon the palletized load, article, package, or product can be reinforced.